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Reference : UMR8608-SLADRA-008
Workplace : ORSAY
Date of publication : Saturday, November 16, 2019
Type of Contract : FTC Technical / Administrative
Contract Period : 12 months
Expected date of employment : 1 January 2020
Proportion of work : Full time
Remuneration : Between 2 470 and 2 850 euros net salary per month, depending on the experience.
Desired level of education : PhD
Experience required : 5 to 10 years
Full time position is at the Institut de Physique Nucléaire d'Orsay France (IPNO), in the “Energy and environment” team.
The subject proposed is part of a broad research program devoted to complex formation studies of d- and f-elements in the presence of organic complexing agents. This program was financially supported by the CNRS-co-funded national program NEEDS Environment (2013-2018) and is currently financed by the ANR (The French National Research Agency) project “PLUTON” (2018-2022).
The release into the environment of highly toxic actinides (An) and other radionuclides (RN), as a consequence of nuclear accidents, weapon tests, uranium mining and milling operations, or waste processing/disposal, contributes to the radioactive contamination of soils and water. The transfer of metal cations in soils and sediments is not only controlled by geological and physico-chemical parameters (clay and organic matter contents, pH, Eh, etc.) but also by microorganisms. As a matter of fact, the latter take part in the mobilization/immobilization of trace metals . Therefore, the presence of actinide(IV) (Pu, Th, etc.) contaminants after accidental discharges raises the question of their transfer in the environment and the resulting risk of food chain contamination.
Siderophores, as specific natural chelators of iron, must be considered in this context . Bacteria and yeasts excrete these low molecular weight soluble compounds in water to overcome the limited bioavailability of iron under aerobic conditions by assisting in the dissolution of iron oxohydroxides in soils.
Gadd GM (2010) Microbiology 156: 609-643.
(a) Braud A, Hubert M, Gaudin P, Lebeau T (2015) J Appl Microbiol 119: 435-445. (b) Ferret C, Sterckeman T, Cornu JY, Gangloff S, Schalk IJ, Geoffroy VA (2014) Env Microbiol Rep 6: 459-467. (c) Hazotte AA, Péron O, Abdelouas A, Montavon G, Lebeau T (2016) Chem Geology 428: 8-14.
At the Institute of Nuclear Physics of Orsay (IPNO), studies have been conducted recently on various U(VI)-hydroxamic acid systems [3-4]. The U(VI) and Pu(VI) complexation equilibria with the ligands of environmental interest have been also investigated over the last years . The combination of different experimental techniques with theoretical calculations (DFT) has led to the determination of fundamental data relative to complexes of metal ions with organic ligands that allowed to predict the migration behavior of these radiotoxic elements in the environment.
In the continuity of previous studies, the proposed work is focused on the speciation of Pu(IV) in the presence of hydroxamic siderochelate derivatives. The literature data on complexation of Pu(IV) with hydroxamic acid ligands are very rare. The aim of this project is to characterize the Pu(IV) binding properties of siderophores in solution from both structural and thermodynamic viewpoints for checking their efficiency in terms of affinity and selectivity. Zr(IV) and U(IV), as plutonium surrogates can also be studied. Our partner at the Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB, UMR CNRS 6302) will provide new polyhydroxamic acids that will be studied in the frame of the ANR project “PLUTON”. The protonation constants of these ligands will be also determined by affinity capillary electrophoresis at IPNO. Complexation studies of Pu(IV) will be performed by liquid-liquid extraction with detection by scintillation counting. UV-vis spectrophotometry and capillary electrophoresis will also be used.
Sornosa-Ten A, Jewula P, Fodor T, Brandès S, Sladkov V, Rousselin Y, Stern C, Chambron J-C, Meyer M (2018) New J Chem 42: 7765-7779.
Sladkov V, He M, Jewula P, Penouilh M-J, Brandès S, Stern C, Chambron J-C., Meyer M (2018) J Radioanal Nucl Chem 318: 259-266.
(a) Sladkov V (2013) J Chromatogr A 1289: 133-138. (b) Sladkov V (2014) J Chem Therm 71: 148-154. (c) Sladkov V (2016) Electrophoresis 37: 2558-2566. (d) Sladkov V, Bessonov AA, Roques J, Charushnikova IA, Fedosseev AM (2018) New J Chem 42: 7780-7788
• Solution chemistry
• Chemistry of actinides and heavy metal ions
• Handling of radioactive elements
• Liquid-liquid extraction
• Scintillation counting
• Capillary electrophoresis, UV-vis spectrophotometry
• Language: English
• Autonomy, organizational capacity and ability to report
• Ability to communicate and argue, analysis, synthesis and critical thinking
• Ability to learn and develop skills, flexibility and adaptability, creativity
The « Institut de Physique Nucléaire d'Orsay » (IPN), created more than 50 years ago on the initiative of Irène and Frédéric Joliot-Curie, is today at the heart of the scientific and technical pole of the Greater Paris region. It is one of the most important laboratories in the world undertaking nuclear physics research that is centered on the nature of matter and its ultimate constituents.
A unit of the CNRS (Centre National de la Recherche Scientifique) and the Université Paris-Sud, the IPN is a leader at both national and international levels. It plays a vital role in experiments being carried out by wide-ranging collaborations at major experimental facilities most notably in Europe, the United States and Japan.
L'IPN qui exploite en outre deux accélérateurs (ALTO et le Tandem), est fort de plus de 350 collaborateurs, chercheurs, ingénieurs et techniciens. Ces ressources lui permettent de mener des recherches en physique nucléaire, en physique des astroparticules, mais aussi dans les domaines de la radiochimie et des champs pluridisciplinaires.
350 permanent staff performing or supporting IPN research projects
Two on-site accelerators recognised under the European label « Transnational Access (TNA) » Facility
200 published scientific articles per year
For further information please contact Dr. Sladkov (firstname.lastname@example.org).
research engineers interested in the position are requested to submit a motivation letter, a CV to Portail Emploi CNRS : https://emploi.cnrs.fr/
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